1. Field of the Invention
The invention relates to a cutter for the deburring of bores, comprising a rectangular edged cutting element having taperingly extending cutting edges, having rakes ground with back taper and an end contact surface on the cutter head intended to be placed in contact on the inner surface of a bore.
2. Description of the Prior Art
Cutters of this nature intended for the deburring of bores are preferably utilised in pairs, the cutting blades comprising radially outwardly turned tapered cutting edges installed in a rectangular reception slot in a rotationally driven tool holder. The cutting blades are thrust outwards via pins on a shaft by means of a spring situated within the tool holder, the pins each engaging in a groove of the cutter elements. According to German Pat. No. 2,649,208, the cutting blades are equidirectionally displaceable. The cutting blades in the inoperative position thus protrude radially outwardly under spring force. In the operative position during the deburring of a bore, the cutting blades are progressively displaced inwards against the spring force as the tool holder is fed in, because of the tapered extension of the cutting edges in the case of bevelling bore edges, until they finally reach the inner area of the bore whilst in rotary motion.
The tool holder is then displaced together with the cutting blades through the bore so that it may process the rear bore edge during the return working feed.
The cutting blades furthermore have another cutting edge on an opposing side, so that following the traversal of the bore, the rim of the bore may be deburred and chamfered during the same cutting sequence but in another feed direction, from behind.
In this connection, it is disadvantageous in the case of such known cutters that the chamfer just produced, and also the inner surface of the bore within its internal volume, may be damaged upon terminating the processing operation during continued inward radial displacement of the cutting blades or cutters for traversal of the bore.
In a known cutter, the cutter blades may easily be jammed in the tool holder by swarf penetrating into the blade guide, thus damaging the inner surface of the bore during traversal of a bore for the purpose of deburring the rear side. The risk also arises in the case of the known cutter that it can be wrongly inserted in the tool holder, making the tool unserviceable for operation and cutting or damaging the bore.